Work holding device



Get. 20, 1942.

E. BARNES WORK HOLDING DEVICE Filed NOV. 22, 1939 fnwcntor j Gum-negPatented Oct. 20, 1942 UNITED STATES PATENT OFFICE WORK HOLDING DEVICEEdwin Barnes, Marshall, Tex.

Application November 22, 1939, Serial No. 305,587

3 Claims.

My invention relates generally to clamping devices, and moreparticularly to a clamping device for holding several pieces of work atthe same time.

An object of my invention is to provide a clamp for clamping a singlepiece of work, or several pieces of work, in line upon the bed of aplaning mill or similar machine.

Other objects and advantages of my invention will become apparent from areading of the detailed description of the invention in connection withthe drawing illustrating a preferred form of my invention.

In the drawing:

Fig. 1 is an elevation view of my work holding device showing a numberof pieces of work held clamped in line with one another and clamped downon the bed of a machine.

Fig. 2 is an enlarged perspective view showing more details of thecenter clamping member of my work holding device in holding position.

Fig. 3 is an end elevation view of the center clamp member.

Fig. 4 is a side elevation view of the center clamp member, and

Fig. 5 is an enlarged broken perspective view of an end clamping memberof my work holding device.

In the drawing B designates the work bed of a machine carrying my workholding device. The

letter W designates pieces of work held by my work holding device. Thespacing strips designated by letter S serve to hold the work off thebase of the working plate of the machine. While these spacing strips Scooperate with my work holding device, they are not to be considered asan essential part of the combination of elements making up my workholding device. The special function of the strips S is to elevate thework such as an unlevel casting or the like, above the working surfaceof the machine to prevent any tendency of the casting, or the like, fromrocking after it is clamped.

The end clamp I consists in a rectangular steel slab which is providedwith longitudinal biting edges along one of its longest faces.

The end clamp I is urged up against the work W by means of a screw andpressure bar combination comprising a set screw 2 threaded through apressure bar 3 to contact the clamp I. The pressure bar is preventedfrom backing up due to the reaction of the screw 2 on the clamp I bymeans of the spacer pins 4 shown in Fig. 1

mounted in a pair of spacer pin holes 5 shown 55 by the dotted linesthrough the base B of the machine.

The center clamps designated generally by numeral 6 are provided withlong biting edges I on both of their longer sides so that they bite intoopposing pieces of work when pressure is applied to the end clamps I.

The center clamps 6 are slidably held to the base B of the machine bymeans of flat headed clamping bolts 8 whose heads 9 slide in T shapedgrooves in the bed B below its working surface.

The vertical position of the center clamp is controlled by the clampingnuts II] on the clamping bolts 8. The center clamp is provided with arecess II into which the nut I0 fits. This recess is important in thatit prevents the nuts from extending above the clamp 6 itself tointerfere with the cutting of the work W. When very thin work is beinghandled the upper face of the clamp sometimes must be set close to theface of the work being out.

My invention, broadly speaking, is the combination of two end clamps andone or more center clamps slidably mounted in a machines work bed B on aline connecting the end clamps. The work W, held in my work holdingdevice, may be machined on its upper face and both side faces with onesetting. The number of pieces of work to be machined is limited only bythe length and width of the bed B of the machine and the number of toolheads or milling cutters employed. Fig. 1 of the drawing illustrates aset up of three pieces of work W being held by the use of two centerclamps 6. Obviously additional center clamps would be used if more thanthe three pieces of work W were set up.

In practice, the work is placed over the longitudinal slots of the bedof the machine with center clamps 6 in place between the pieces of workW. Suitable parallel strips S are used to elevate the work W to provideclearance. At; each extremity of the series of pieces of work W there isplaced an end clamp I backed up by a: pressure bar 4, set screw 2, andspacer pins 4, as described above for the purpose of tightening the workW. While my Work holding device would operate with a single pressureapplying device of the style described above, or some other type ofpressure applying device, the use of the two pressure applying deviceshave been found to be of advantage. I have illustrated my inventionshowing the use of the two pressure applying devices, but it must beunderstood that I am not limiting my invention to the style shownemploying two pressure applying devices.

Usually when a series of pieces of work are clamped in line with oneanother, using my work holding device, the pieces of work W buckleslightly. This buckling may be deliberately brought about if desiredwhen extreme pressure on the work W is needed. After the end pressurehas been applied on the series of end and center clamp and pieces ofwork W, the center clamp 6 may be pulled down to the bed B of themachine by means of the bolts 8 and the nuts II]. This movement of thecenter clamps takes out all of the slack in the assembled work W andcauses the biting edges on the clamp to bite still further into work W.This extreme clamping pressure is peculiar to my invention. As

ing threaded engagement with the said pressure bars and having contactwith the said work far as applicant is aware of it, such high pressurecannot be obtained by any of the prior artwork holding means.

of construction or arrangement of parts'making up my work holding deviceas herein illustrated and described, for it is apparent that variouschanges in size and arrangement of parts maybe resorted to withoutdeparting from my invention.

My clamping device may be constructed out of hard steel or othersuitable materials.

Having thus described my invention, I claim:

1. A work holder of the class described comprising a pair of opposinglongitudinally adjustable pressure applying end clamps, each of said endclamps being provided with an anchoring means for anchoring the same toa machine bed or the like, said anchoring means including a pressure barwhich extends across a pair of spacer pins extended up from the machinebed each of said end clamps being provided' with clamping jaws includinghorizontally extending knife edges adapted to bite into a piece of work,and a work separating and holding clamp provided with a verticallyadjustable attaching means for attaching it to a machine bed or thelike, said attaching means comprising a clamping bolt including a headadapted to slide in a T slot in a machine bed, said separating andholding clamp being positioned in line with and between the said endclamps and being provided with parallel faces each of which is providedwith knife edges adapted to bite into pieces of work.

2. A work holder of the class described comprising a pair of opposinglongitudinally adjustclamping jaws and a work separating and hold- 7 ingclamp provided with a vertically adjustable attaching means forattaching it to a machine bed or the like, said attaching meansincluding a clamping bolt having a head which is adapted to slide in a Tslot in a machine bed or the like, said separating and holding clampbeing positioned in line with and between the said end clamps, saidseparating clamp being provided with parallel jaws each of which isprovided'with horizontally extending knife edges adapted to bite intopieces of work.

3. A work holder of the class described comprising alongitudinally'adjustable pressure applying end clamp, an anchoringmeans for anchoring the adjustable end clamp to a machine bed, saidanchoring means including a bar suspended across a pair of anchoringpins extending up from the machine bed, the saidend clamp including ajaw provided with longitudinally extending knife edges adapted tobite'into a piece of work, a separating clamp including a pair ofparallel work engaging faces, each of which is provided with a series oflongitudinally extending knife edges adapted to bite into pieces of workseparated by the said separating clamp, a vertically adjustablefastening means for holding the said separating clamp to the machine bedor the like and an end clamp provided with a work contacting faceprovided with a series of parallel horizontally extending knife edgesadapted to bite into a piece of work, said end clamp being provided withan anchoring means for anchoring it to the machine bed, or the like.

EDWIN BARNES.

